Minnesota: Follow-up bio-monitoring project – Some answers, but more questions

OAKDALE – Less than one week after state officials announced that a follow-up bio-monitoring project showed drops in PFC levels in 164 volunteers, residents attending a state Department of Health open house here Monday night learned there are still more questions about PFCs than answers.

The MDH public meeting at Oakdale’s Skyview Elementary School was held to explain results of a 2010 bio-monitoring study that followed the initial 2008 East Metro PFC Bio-Monitoring Pilot Project. The follow-up results showed levels of PFOS in test subjects declined 26 percent, PFOAs declined 21 percent and PFHxS declined 13 percent.

What MDH staff could not tell residents, however, were the long-term effects of PFC exposure and if there are more PFC sources besides drinking water in the Lake Elmo, Oakdale and Cottage Grove test areas that residents are exposed to.

MDH Epidemiologist Dr. Jessica Nelson said that although seven PFCs were measured in the 2008 study, PFOS, PFOA and PFHxS were found in all 2008 study participants. She added that all study volunteers were adults ages 20 years and older and evenly split among the three affected communities.

The follow-up bio-monitoring results released last week indicate the state’s efforts to filter drinking water sources in the three communities are working to reduce PFC levels, she said.

“The drinking water is in good shape,” Nelson said.

Speaking to residents at the open house, Nelson said the MDH initial study showed drinking water was the source of PFCs found in the 2008 blood tests.

“In the case of groundwater contaminated by PFCs, drinking water was the major source,” she said.

Since 2008, Oakdale has used carbon filters on several city wells to remove PFCs. Lake Elmo residents with private wells have either been provided with carbon filters by the state or encouraged to install their own filters or reverse osmosis filtering systems, according to MDH hydrogeologist Ginny Yingling.

But Nelson noted that although the MDH study shows PFC levels declining, the chemical lingers in the body, especially in older people or those who have lived in one location for a long period of time.

“These chemicals are persistent in the body,” she said. “PFC levels tend to be higher in older people and people who have lived in their houses a long time. One interesting finding from the project, and this is one we’re going to be looking at, is that not all participant’s levels went down.”

“One of the big unknowns is what are other sources,” Yingling added.

Nelson said volunteers tested in the follow-up bio-monitoring are being asked to complete a 14-page questionnaire that researchers will analyze for other possible PFC exposure sources.

Those possible PFC sources might include diet, occupations and consumer products used, Nelson said. She added that other factors looked at are did participants eat fish from area lakes and the Mississippi River, biological differences in how PFCs are cleared from the body and did some follow-up participants have lower PFC levels in their 2008 samples.

Another factor affecting the follow-up study, Nelson said, is the legislature funded the PFC research through 2012. She added that lawmakers will have to find more money in the 2012 session that starts in late January so the MDH can continue PFC research.

And Nelson admits that one difficulty in researching PFC exposure is there have been few studies done on the issue worldwide.

“Scientists still don’t fully understand the effects of PFC exposure,” she said. “There’s not a clear indication that PFCs are a risk for disease.”